It is sometimes claimed that non-human animals (and perhaps also young children) live their lives entirely in the present and are cognitively ‘stuck in time’. Adult humans, by contrast, are said to be able to engage in ‘mental time travel’. One possible way of making sense of this distinction is in terms of the idea that animals and young children cannot engage in tensed thought, which might seem a preposterous idea in the light of certain findings in comparative and developmental psychology. I try to make this idea less preposterous by looking into some of the cognitive requirements for tensed thought. In particular, I suggest that tensed thought requires a specific form of causal understanding, which animals and young children may not possess.